Direct Metal Laser Sintering Meets Formula-1 – Next Up Product Prototypes?

At my house, it’s not enough to love great products and every detail of how they were made. That fact is obvious to anyone who’s seen my less-than-interested daughter hold her ears and run out of the room screaming at the first peep of conversations involving “machining” or “part line.” Product design infatuation was clearly part of our marriage vows, along with brewing strong coffee, making soufflé, and having and holding until the end. But those who know my situation best know that a keen love of motorsport was also part of the pre-nup. So when Formula 1 starts using a new method of rapid prototyping in metal, well, the pairing of the two topics—racing + product—seems almost cause for a celebration where I live, or at least a multi-hour discussion of the method’s potential over dinner with our equally obsessive friends.

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Real Metal Parts from an Astonishing Prototyping Process
(photo courtesy of 3T RPD)

Race Tech, a publication widely read among what must be tens of fans across the English speaking world, had an article in its January issue about Direct Metal Laser Sintering (DMLS) getting some traction with Formula-1 teams. This excerpt might pique your interest:

Advances in the latest sintering technology are likely to turn the whole design rulebook completely on its head and enable designs in metal that would have been completely impossible in earlier times. Design practices associated with traditional manufacturing—turning, milling, drilling and other techniques—could in the future no longer apply and components will be designed solely on their functionality.

To take simple example, holes could be positioned more accurately and in places where previously drill access was totally impossible. The possibilities are endless! Gone also is the concept of tolerance dimensioning because in theory, at least, every part made using DLSM [sic] is exactly the same as the previous one. The future, at least in design and manufacturing, starts here.

Metal parts without machining, casting or tooling! Parts that are functionally near-manufacturing durability and can be used for testing, assembly trials and final design validation!? I imagine this technology having a similar impact to when stereolithography (SLA) took off. Only in this case, the parts are durable, with finishing could emulate a final manufactured part, and can have details that were never possible with conventional fabrication methods. Just to be 100% clear, they are putting these prototype parts in actual cars and using them to test.

For comparison, consider nylon sintering, called “Selective Laser Sintering” (SLS), if you are familiar with that approach. SLS for prototyping plastic parts has been around a bit longer and is a lot more accessible than metal sintering in terms of availability and cost. Nylon sintering makes durable parts, but the parts are hard to finish relative to an SLA, for example, which can be easily sanded. Metal laser sintering, on the other hand, is made with much finer layers than its nylon cousin, which means it has a nicer surface to begin with, has greater strength in the z-axis, and—with finishing— is as cosmetically beautiful as a “real” part.

nylonchain

Nylon Chain Mail Part Shows How Sintering Allows Detail Not Possible with Traditional Fab Methods – This Mesh Is Constructed As All One Part, Not Put Together from Separate Rings
(photo: MindTribe)

DMLS works by melting a powdered material layer-by-very-fine-layer with a laser. The powdered substance contains a mixture of hard and soft materials. (The composition of the powders appears to be undisclosed and proprietary.) The build platform is currently 250mm x 250mm x 215mm high (10″ x 10″ x 8.5″). At each layer, the laser melts the softer substances so that the harder, higher melting point metal is held in suspension. The fusing process has evolved to the point that it almost completely melts the entire powdered mixture. And perhaps more exciting, the alloys have evolved to include not only bronze and nickel but also different steels and even titanium.

DMLS can produce parts with comparable or better properties than casting, including tensile strength, yield strength and elongation, but it cannot yet meet tightest tolerances and surface finish requirements without secondary machining, bench work and polishing.

engine_exhausts

Metal Sintered Engine Exhaust Parts Can Be Put in a Car and Tested
(photo courtesy of 3T RPD)

The DMLS machine, which is made by EOS, starts at a pricey $600K to buy, but supposedly some model shops are starting to have them. Given that the technology has only recently moved from the aerospace industry to Formula-1, that bastion of low-cost engineering prototyping (cough), most of these model makers are near the motorsport centers in Europe.

Sue Burnip from 3T RPD in the UK helped me out with all of the photos of the metal parts for this blog. 3T RPD specializes in SLS and DMLS, and is one of the largest LS providers in the UK – home of several F-1 teams. (Race enthusiasts may be interested in 3T RPD case studies, including work for the Jordan-Honda team.)

aerospace_1

Aerospace Part Made with DMLS and Secondary Finishing
(photo courtesy of 3T RPD)

In the SF Bay Area, I found Prototypes Plus to be the only local option for sintering, but only nylon sintering, which is interesting but not METAL. Dylan Ternes showed MindTribe the EOS SLS machine and some samples of nylon sintered parts, including parts made with a small percentage of carbon, glass, and aluminum. He explained that the nylon-based parts seem best suited for prototyping plastic components that are functional pieces on the inside of a product and for not the cosmetic outer enclosure.

While Prototypes Plus does offer secondary processes for making the SLS parts cosmetic, the approach doesn’t lend itself to finishing the way SLAs do. Prototypes Plus plans to get a DMLS machine in the future. Dylan has personally checked them out, and he says the metal sintered parts are truly awesome. He adds that metal sintering is “really expensive” at this time.

dylan

Dylan at Prototypes Plus Discusses Laser Sintering

nylonthingy

Complex Part that Prototypes Plus Made with Laser Sintering
(photos: MindTribe)

My colleague Lionel provided a sample part made with nylon sintering that might help bring home the truly marvelous flexibility of this approach. The spring hook, including the captured functional spring, rotatable strap feed, and other moveable features, was made as a “single part” using nylon laser sintering. This part is not brittle like an SLA would be, so it does not break in use.

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Spring Hook with Functional Captured Features Made AS A SINGLE PART with Sintering

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Nylon Laser Sintered Parts Are Not Brittle Like SLAs
(photos: MindTribe)

Just to wrap, as I consider some of the metal details of products my husband has worked on, it occurs to me that metal prototyping may have taken months of quality time away from my marriage. I am sure I watched a lot of F-1 on my own in the 2006 season, in particular. Indeed, my product-consumed partner seems to salivate over the Race Tech article, and I vow to find out more about these machines and how far they are to becoming accessible – if not for the rest of us, at least for those like Apple who can afford to take the pole position for new design methods.

nylonhands

Dyed Nylon Sintered Hands
(photo: MindTribe)

Posted by & filed under MindTribe Tech.

11 Responses to “A Drool-Worthy Process for Rapid Prototyping of Metal Parts”

  1. Adam

    This is a very cool post.

    Wanted to chime in from my desk at the Tribe to share a similiar rapid prototyping technology I’m familiar with. If anyone around here has examined the trinkets on my desk recently, they might have seen a miniature version of the Hagia Sophia, made of ceramic. It was made using a process called Three Dimensional Printing or 3DP. I had an internship in the 3DP lab at MIT during the summer of 1998.

    3DP Hagia Sophia

    The 3DP process is very similar to direct laser sintering. As with direct laser sintering, powder is deposited in layers. But instead of each layer being laser sintered, the powder is bound together with binder, deposited by an ink-jet print head. The binder is cured quickly with an infrared lamp, the next layer is spread, and process continues until the whole part is built. The part is then in a “green” state — still quite fragile, and over-sized. It then goes to a sintering step, where the “green” part is heated, so the powder particles are sintered together, the binder material burns away, and the part shrinks to its proper size.

    3DP can make plastic, metal, and ceramic parts. There was even the potential for printing consumables, such as time release drug capsules with separate chambers containing different drugs. The technology has been licensed to a number of startups, each with a slice of the potential-application pie. Here’s a quick survey:

    Zcorp – Licensed 3DP for plastics. Currently selling printers.

    Soligen – Licensed 3DP for ceramic molds to make metal casting.

    Therics – Licensed 3DP for for making synthetic bone.

    While the ceramic Hagia Sophia is pretty sweet, I can’t wait until I have a 3DP or laser sintering printer on my desk!

    – Adam

    Reply
    • Lori H.

      I guess Forecast3D outsources it. They no longer have the machine in-house. They can still arrange it.

      Reply
  2. Lori

    Hey Lynette:

    Be sure to let us know how the experience goes and if your client faints over the price.

    Best,
    Lori H.

    Reply
  3. Steve

    Back before the public became cognizant of hybrid technology, I retrofitted a compact car with a hydrostatic transmission – a fluid power hybrid. The power plant was an old GS1100 engine and to idealize engine/pump transfer a new primary reduction set had to be made.

    These are ground-tooth gears, chiefly because of the rpms. The blank is machined, then it is strengthened, then surface hardened. Finally, the teeth are ground to spec. This is one example of something DMLS cannot do – since the cross-sectional properties vary. And it has nothing to do with composition. Also, that some DMLS output cannot be made any other way is true only if there can be no assembly. Notwithstanding these comments, DMLS is a frontier technology and countless possibilities remain undeveloped.

    Perhaps a larger reason DMLS is not in still wider use, is simply because complex output rarely contains within itself any information about how the piece will be manufactured. So, for product development purposes, IMHO, DMLS should be reserved for instances where a design decision cannot be made otherwise. What good will it do to hand a customer one of something they intend to manufacture, then say “oh… you want to make a lot of these?” If a new design were intended for high volume manufacture, wouldn’t you necessarily consider corresponding manufacturing methods and technologies all along the way?

    BTW, did you get to visit the BMW F1 track at CES? Rahal was there.

    Cool post, thanks for allowing me to comment.

    Reply
  4. Lori

    Hey Steve-

    It’s a good point that one might be able to design something that you could never subsequently make in any traditional sense, and “testing” takes on a different meaning when it is a part with different cross-sectional properties than what one would see in production. Still, I bet you’d agree that we get a lot of mileage out of other prototyping methods that are even worse in both these areas, no?

    Damn! I am embarassed to admit that I didn’t make it to CES this year, so I missed the BMW F1 track and Rahal team! Now that’s a reason to go again. My interest was waning since rarely is there anything new worth seeing there anymore, so unless I have some good meetings setup, I don’t need to see the world’s biggest flat panel again.

    Next year let’s plan a CES trip in advance by scoping out who is actually doing something interesting! Maybe we could get Samsung to show F1 highlights on its oversized TV instead of that same hermit crab footage.

    Kindly,
    Lori H.

    Reply
  5. csven

    Stumbled across this entry and thought I’d add a late comment to direct your attention to the metal *melting* processes: Electron Beam and Laser Melting. Metallurgical test results, according to some of the reading I’ve done, show this process exceeds forging and approaches casting in quality. For a quick overview, there’s a video on YT that may be of interest to you – http://www.youtube.com/watch?v=4odUhDjKHzo .

    Also, a couple of weeks ago I took a quick tour of American Precision Prototypes’ shop and was interested to see sintered parts infiltrated with wax which they then use in a kind of “lost wax” process. I’ve not compared prices between this process and DMLS, but I suspect it’s a bit cheaper (for now).

    Reply
  6. Lori

    Hey Csven:

    We’ll scope out your recommendations. I am sure other readers will appreciate having a starting point. This seems new enough that finding resources is non-trivial.

    Thanks-
    Lori H.

    Reply
  7. Rapid Prototyping

    Great post, not easy to make the industry interesting, doubly so far your daughter! We haven’t started using sintering just yet but my boss seems pretty interested in moving into that industry soon I think. Looking forward to it.

    Reply

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